Phosphatase and Tension Homolog Overexpression in Insulin Resistant Diabetic Adipose Tissue

Objective To investigate the expression of phosphatase and tension homolog(PTEN) in adipose tissue of KKAy diabetic mice, a mouse model of type 2 diabetes. Methods KKAy diabetic mice were fed with high fat diet for 4 weeks. After blood glucose met the criteria of diabetes(over 16.7 mmol/L), mice were randomly divided into 3 groups: a control group(without any treatment), a rosiglitazone group(treated with rosiglitazone 12.5 mg/kg·d once per day), and a metformin group(treated with metformin 3 g/kg·d twice daily). After 4 weeks, we then determined the expression of PTEN and phosphoserine 473-Akt(pS473-Akt) in the epididymal adipose tissue with Western blots. The mice in each group were further divided into the insulin(-) subgroup and insulin(+) subgroup, which were intraperitoneally injected with saline and insulin(5 mU/g body weight), respectively. Results The expression of PTEN was elevated in the epididymal adipose tissue obtained from KKAy diabetic mice compared with that from the C57BL/6J mice(P<0.001). In accordance with the enhanced expression of PTEN, the level of pS473-Akt stimulated by insulin was decreased in the adipose tissue of KKAy mice compared to the C57BL/6J mice(P<0.001). Treatment with the insulin-sensitizing agents, rosiglitazone and metformin did not inhibit the elevated expression of PTEN in adipose tissue of KKAy diabetic mice. Conclusion PTEN may play an important role in the development of insulin resistance in adipose tissue of type 2 diabetes mice model.